#include <iostream>
#include <cstdio>

using namespace std;
int Max(int a ,int b,int c)
{
	int m = (a > b ? a : b);
	return (m > c ? m : c);
}
int main()
{
	int a,b,c;
	cin >> a >> b >> c;
	double r = Max(a,b,c) * 1.0 /(Max(a + b,b,c) * Max(a,b,b+c));
	printf("%.3lf\n",r);
	return 0;
}
